(1) Field of the Invention
The present invention relates to a method for preventing an inundation or a leakage of water from cracks formed in a concrete structure such as a tunnel, a basement, a dam, a weir, a swimming pool or an outdoor concrete structure, and a device for working this cutoff method.
(2) Description of the Related Art
As the conventional method for preventing an inundation or a leakage of water from cracks of a concrete structure, a method has been adopted in which a V-shaped notch is formed on the surface portion of a cracked concrete structure, a resin-casting tube is inserted in the V-shaped notch, a quick-setting mortar is placed from above to embed the resin-casting tube and fix the resin-casting tube to the concrete wall, a casting nozzle is attached to the resin-casting tube, a urethane type blowing resin is cast through the resin-casting tube, and the cast urethane type blowing resin is foamed on contact with water to intrude into the interiors of crack voids and into branched cracks and effect bonding and curing, whereby a water cutoff effect is attained.
In the conventional cutoff method in which a V-shaped notch is formed, the step of boring a V-shaped notch along the crack on the surface of a concrete wall by drilling, the step of inserting a resin-casting tube, and the step of placing a quick-setting cement are necessary, and a long time is required for completion of the operation. Accordingly, this conventional cutoff method is not suitable for a cutoff operation in a tunnel, which should be completed in a short time. Moreover, according to the conventional method, it is difficult to obtain a complete cutoff effect where the cracks are curved or where many cracks run from the main crack orthogonally thereto or at the periphery thereof.